Method of coating fabrics and products derived therefrom



Oct. 21, 1930. w. c. CALVERT 1,779,383

METHOD OF COATING FABRICS AND PRODUCTS DERIVED THEREF'ROM Filed Dec. 2, 1927 William C. Calveri' Patented on. 21, 1930 ELIAM G. OALVERT, OF EVANSTON, ILLINOIS, ASSIGNOR TO THE GOODYEAR TIRE &

RUBBER COMPANY, OF AKRON, OHIO, A CORPORATION OF OHIO METHOD or COATING FABRICS AND rnonucrs DERIVED THEREFROM Application filefilecember 2, 1927. Serial No. 237,341.

[Q rics of a similar nature.

More specifically, my invention has for one of its objects the provision of a fabric which may be employed in the construction of gas containers for balloons, which is relatively flexible and durable. The fabric also possesses a relatively high resistance to the difiusion of inflating gas through the coating film and yet is comparatively.inexpensive to manufacture.

Heretofore, it has been practically universal practice to construct gas containers for balloons of fabric coated either with a film of rubber or with gold beatefs skin. The first mentioned material is relatively inexpensive to manufacture, because rubber in the form of a cement is inexpensive and may be readily spread over the surface of the fabric by means of suitable calendering rollers. However, fabric so prepared has a relatively high degree of permeability and an excessive amount of inflating gas (hydrogen or helium) is lost by diffusion of the gas through the coating film. Fabrics coated with gold beaters skin are, in many respects, more satisfactor than rubber coated fabric, because such fabrics have a very high re sistance to the diffusion of the infiatin gas and are also quite durable and flexible. ince this material (an animal membrane) is obtained only in small pieces hardly more than six or eight inches square its initial cost is I not only relatively great, but the proper trimming of the small pieces and the application thereof to extensive surfaces as of gas cells, involves a tedious and expensive process. The cost of fabrics coated with this material is, therefore, so excessive as to preclude their use in any except the most expenslve and elaborate of balloons.

Numerous attempts have been made to develop a coating material having the advantages of a rubber coating and also having the durability and the resistance to diffusion of inflating gases characteristic of fabrics coated with gold beaters skin. Durlose acetate,

ing the course of these experiments various materials have been suggested and tried, among which specificreference may be made to the cellulose derivatives, such as cellucellulose nitrate, cellulose xanthate, and proteinous materials, such as gelatin. Heretofore, none of these materials has proved to be entirely satisfactory, either because of a lack of flexibility or because of the impossibility of so applying to the fabric as to provide a tenaciously adhering, permanent coating. 7

This invention consists in the discovery of a novel method of application whereby the materials previously referred to may be caused to adhere readily and permanently to a fabric surface. For a better understanding of the invention, reference may now be had to the single figure of the accompanying drawing, forming a part of the specification and whichis a cross-sectional view of a portion of fabric prepared in accordance with the provisions of this invention. The method of application varies somewhat, depending upon the nature of the fabric surface to which the coating is to be applied. For example, to apply a coating of impermeable material to an ordinary rubberized fabric it is necessary, first, to coat the fabric with a rubber suspension, such as latex or rubber cement. Additional coatings containing gelatin or glue, or other adhesive, which will readily adhere to the coating material, are then .applied to the surface of the first coating and the gas resistant film is then applied to the latter coating.

The exact course of procedure may be varied, depending upon the character and qualv ity of the product desired. The following is a specific example of a procedure whereby a high grade fabric, particularly adapted for the construction of gas cells for lighter-thanaircraft, is obtained from an ordinary rubber coated fabric.

The fabric 5 is first coated with a layer 6 comprising a solution consisting of approximately 200 cc. of 60 percent latex, or its equivalent, and 1000 cc. of water. A second coating 7 consisting of approximately 100 cc. of 60 percent latex, 30 grams of gelatin, 60 grams of glycerine and 1000 cc. of Water is applied to the first coating. A third coating 8 in which the proportion of latex is relatively decreased while the proportion of gelatin is proportionately increased, consisting of 50 cc. of 00 percent latex, 00 grams of gelatin, 120 grams of glycerine and 1000 cc. of water, is next spread oi er the second coating. This layer is followed by one or more (usually two or three) coats of a solution constituting a layer 9 and consisting of 40 grams of gelatin, 80 grams of glycerine and 1000 cc. of water, in which 2.4 grams of alum (a tanning agent) has been dissolved. This solution is spread upon the fabric and is permitted to dry, preferably while the fabric is stretched upon a table or upon a tentering frame. When the coating has practically completely dried the surface thereof is moistened with water by means of a sponge or a brush and the final coating 10 of gas resistant material, preferably in sheet form, is moistened and applied to the adhesive surface of the fabric by means of a roller. The coating material should be rolled until all of the air bubbles are forced from between the gas resistant material and the surface of the fabric.

It will be observed that the initial coat of cementing material is of a composition particularly adapted to adhere to the fabric while each successive coat of cementing material contains a smaller proportion of the substance capable of adhering to fabrics but a larger proportion of material adapted toadhere to the gas resistant film. This construction is highly important because it results in an excellent bond between the fabric and the gas resistant film even though there is no known cement adapted to adhere to both materials simultaneously.

Any suitable gas resistant substance may be employed as a coating material. Ithasbeen observed by experience that the commercial cellulose derivativeknown ascellophane (a precipitated or regenerated cellulose Xanthate), which may be obtained in the form of thin transparent sheets of practically any desired size and thickness, is particularly suitable for the purpose. This material should be moistened with water containing about 5 percent glycerine before it is applied to the fabric.

In case it is desired to apply a gas resisting film to an ordinary uncoated fabric, it is not necessary to employ latex containing solutions in order to obtain adhesion of the cementing material to the fabric. Instead, a number of coats (preferably five or six) of a solution consisting of 40 grams of gelatin, 80 grams of glycerine, 1000 cc. of water and 2.4 grams of alum (a tanning agent) may be applied to the fabric and dried. The drled surface is then moistened with water by means of a sponge or brush and the gas resistant film is applied in the same manner employed in connection with rubberized fabric.

One of the extremely important features of the invention consists in drying the cementing film before the application thereto of the gasresistant material, and this appears to be essential in order to obtain satisfactory results.

Materials prepared in accordance with the methods previously described have a high resistance to the diffusion of inflating gases. They are also flexible and durable and the coating material adheres tenaciously to the surface of the fabric. The coating may also be protected by the application of additional coats of varnish or aluminum bronze or any other desirable coating material, although the latter steps are not essential to the invention.

In addition to having excellent properties as gas retaining media, fabrics prepared in accordance with the method described may be manufactured at relatively low cost, because sheet cellophane, or equivalent materials, may be obtained at a small fraction of the initial cost of gold beaters skin of a quantity SllfllCleIlt to coat a gas cell. Also, since the materials may be obtained in relatively large sheets, one of which is sufficient to cover an entire width of fabric, it may be much more speedily and economically applied to the fabme than gold beaters skin. Furthermore, these materials may be obtained in sheets that are practically uniform in character throughout, whereas gold beaters skin is likely to contain numerous small punctures difficult to detect. Fabrics coated with the former, therefore, require much less careful inspection than fabric coated with gold beaters skin.

Although I have described in detail only the preferred embodiments of the invention. it will be apparent to those skilled in the art that it is not so limited, but that various minor modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

What I claim is:

1. A method of coating fabrics which comprises spreading thereon a film of cementing material adapted to adhere thereto, applying a second coating of cementing material adapted to adhere to a film of material having different adhesive properties from the fabric, drying the cementing materials, moistening the outer surface thereof and applying the film thereto.

2. A method of applying films of coating material to fabric which comprises coating the fabric with cementing material adapted to adhere thereto, applying successive coats of cement containing a material adapted to adhere to a film having different adhesive properties from the fabric, the proportion of the latter cementing material being progressively increased in succeeding coats, drying the cementing coatings, moistening the surface thereof and applying the film thereto.

3. A method of applying gas-resistant ma- 5. A method of coating fabrics with sheets of regenerated cellulose which includes applying to the surface of the fabric successive coats of a gelatin solution, drying the coats, moistening the surface thereof and applying a coating of moistened cellulose material.

6. A method of applying cellulose films to 7 rubber coated fabric which comprises coating the surface of the fabric with a suspension of rubber, applying additional coatings of a solution containing gelatin, dryin' the coatings, moistening the surface thereo and v applying a sheet of cellulose material thereto.

7. A method of applying regenerated cellulose to fabrics which comprises coating the fabric with-a cementing material, drying the cementing material, moistening the surface thereof and applying a sheet of moistened regenerated cellulose to the moistened surface.

8. A method of applying regenerated cellulose to rubberized fabrics which includes coating the fabric with an emulsion of rubber, applying to the latter coating a solution containing gelatin, allowing the gelatin coating to dry, moistening the surface thereof and applying thereto a film of moistened regenerated cellulose.

9. A method of" manufacturing lighterthan-aircraft fabrics which comprises coating the fabric with a solution containing gelatin, drying the gelatin, moistening the surface thereof and applying thereto a film of a cellulose derivative.

10. A method of manufacturing lighterthan-aircraft fabrics which comprises coating the fabric with a solution containing gelatin, drying the gelatin, moistenin the surface thereof and applying thereto a of regenerated cellulose.

11. A balloon fabric having a plurality of coatings of a cementing material applied thereto, the inner-layers of which consist essentially of rubber and the outer layers of which consist essentially of gelatin and an "outer ply of regenerated cellulose adhering to the elatin containing layers.

"12. g balloon fabric havin one coating consisting essentially of rub er, an additional coating consisting essentially of gelatin and a sheet of regenerated cellulose cemented to the latter coating.

In witness whereof, I have hereunto signed my name.

Signed at Evanston, in the-county of Cook and State-of Illinois, this 29th day of November, 1927.

WILLIAM C. CALVERT. 

